A quantum dot is a semiconductor nanometer structure that confines conduction band electrons, valence band holes and excitons in three spatial directions. This confinement can be attributed to the factors: electrostatic potential (generated by external electrodes, doping, stress or impurity), interface between two different semiconductor materials (for example in self-assembling quantum dots), semiconductor surface (such as semiconductor nanocrystal) or combination of the above. Quantum dots have discrete quantized energy spectrum, and the corresponding wave function is located in the quantum dot in space, but extends across several crystal lattice periods. One quantum dot has a small amount of (1-100) electrons, holes or hole-electron pairs, that is, the quantity of electricity it carries is an integral multiple of element of electric-charges.
Quantum dot, also known as nanometer crystal, is a nanoparticle constituted of II-VI group or III-V group elements. The particle diameter of a quantum dot is generally between 1˜10 nm. Since electrons and holes are quantumly confined, continuous energy band structure is transformed into discrete energy level structure with molecular characteristic, which can emit fluorescence after being stimulated. Based on the quantum effect, the quantum dots have wide application prospects in solar cells, illuminating devices, optical organism markers. Many different methods have been proposed to manufacture quantum dots, and quantum dot display products have been developed.